Description: This workshop is concerned with applying formal methods to fundamental issues, with an emphasis on probabilistic reasoning decision theory and games. In this context “logic” is broadly interpreted as covering applications that involve formal representations. The topics of interest have been researched within a very broad spectrum of different disciplines, including philosophy (logic and epistemology), statistics, economics, and computer science. The workshop is intended to bring together scholars from different fields of research so as to illuminate problems of common interest from different perspectives. Throughout each academic year, meetings are regularly presented by the members of the workshop and distinguished guest speakers and are held alternatively at Columbia University and CUNY Graduate Center.

Abstract. There are many cases in which knowledge has negative value and a rational agent may be willing to pay for not being informed. Such cases can be classified into those which are essentially of the single-agent kind and those where the negative value of information derives from social interactions, the existence of certain institution, as well as from legal considerations. In the single-agent case the standard examples involve situations in which knowing has in itself a value, besides its instrumental cognitive value for achieving goals. But in certain puzzling examples knowing is still a cognitive instrument and yet it seems to be an obstacle. Some of these cases touch on foundational issues concerning the meaning of objective probabilities. Ellsberg’s paradox involves an example of this kind. I shall focus on some of these problems in the later part of the talk.

Abstract. The BDI theory says that people’s actions are influenced by two factors, what they believe and what they want. Thus we can influence people’s actions by what we choose to tell them or by the knowledge that we withhold. Shakespeare’s Beatrice-Benedick case in Much Ado about Nothing is an old example. Currently we often use Kripke structures to represent knowledge (and belief). So we will address the following issues: a) How can we bring about a state of knowledge, represented by a Kripke structure, not only about facts, but also about the knowledge of others, among a group of agents? b) What kind of a theory of action under uncertainty can we use to predict how people will act under various states of knowledge? c) How can A say something credible to B when their interests (their payoff matrices) are in partial conflict? When can B trust A not to lie about this matter?